A geofence in a mapped area is a virtual boundary created using location sensing technology on mobile devices (e.g., smartphones, tablets, laptops, wearable computers, etc.). The geofence is generated as a virtual predefined set of geographical boundaries. When a registered location-aware mobile device crosses a geofence, a notification is generated. The notification is sent to a registration server and to any pre-arranged or pre-registered mobile device or email account.
Identifying the location of a mobile device accurately has become a necessity in many applications such as geo-fencing, geo-location, mobile tracking, personal identification, etc. For example, global positioning systems (GPS) using satellites and cell towers (e.g., triangulation method) for location fixing of mobile communication devices (MCDs), such as cell phones, tablets (e.g., iPad®) and the like, have become more common with the widespread use of mobile communication devices and wireless connectivity. While location (or position) fixing capability has improved over the past years, there are still improvements to be made. For instance, current location fixing methods generally use a geo-positioning satellite or triangulation using local wireless towers and available sensors to identify and fix the location of a MCD. The positioning accuracy of such location fixing methods, however, is inadequate due to the inaccuracies of the sensors and/or reflections from the MCD's surroundings (e.g., neighboring geographical and manmade structures). Such inaccuracies and reflections generally cause an identified location to bounce around in a very haphazard way, and the location error introduced by them can be within a range of up to three miles, thereby making any geofences deployed very erratic in controlling access to locations. The large error boundary of the location also creates false alerts when geofences are implemented, which limit the effectiveness of the geofences.
As an example, referring to FIG. 1, which is a diagram illustrating a conventional location sensing (or fixing) system. As shown, location sensing system 100 may include an MCD 101, wireless or cell towers 102-1 and 102-2, a WiFi base station 103, GPS satellites 105-1 and 105-2, and a tracking and monitoring server (TMS) 107 coupled or connected to a display device (e.g., a computer monitor, television, and the like) having display screen 108.
As further shown in FIG. 1, GPS satellites 105-1 and 105-2 are used to generate a location fix for MCD 101. Wireless towers 102-1 and 102-2 or WiFi base station 103 are also used to fix the location of MCD 101, for example, by triangulation. This location information is transmitted over network 106 (e.g., a cloud service) to TMS 107 where it is displayed at the display screen 108. TMS 107 also ensures that the location information is provided to MCD 101 for display on a display device of MCD 101, and saved as historical information in a data store (e.g., a database).
FIG. 2 is a diagram illustrating a display device that displays a map using a conventional location fixing method. Referring to FIG. 2, a display device 200 includes display screen 108 that presents or displays a representation of a map 250 including location 210 of MCD 101, major roads 201, minor roads 202, and locations of buildings 203 and 204. As previously described, the accuracy of location 210 can be dependent on the sensitivity of the sensors (e.g., GPS, gyroscope, accelerometer, compass, barometer, etc.) used to fix location 210, and the error boundary of location 210. The possible error in this prior art scenario is indicated by error radius 212. Therefore, the actual location of MCD 101 can be anywhere within the limit of error radius 212, which defines error boundary 211. That means, for example, that even when the MCD 101 is actually within the building 203, the location of the MCD 101 (e.g., location 210) may indicate that MCD 101 is located outside of building 203. Such position error has been found to be as much as one (1) to three (3) miles when using such conventional method of location fixing.
Referring to FIG. 3, which is a diagram illustrating a display screen displaying a conventional geofence, display screen 108 may display geofence 301 defined or setup by sensors of MCD 101 (e.g., GPS, gyroscope, accelerometer, compass, barometer, etc.) using historical information saved in a data store (not shown) that is coupled to or installed on TMS 107. In the example shown in FIG. 3, geofence 301 is defined to encompass building 203. Accordingly, when a user of MCD 101 enters or exits geofence 301, for example to access roads 201-202 around building 203, an alert (e.g., a notification, email, text message, and the like) may be generated and sent to MCD 101 and/or another MCD, for example by TMS 107. Such geofence 301, for example, can be utilized in a child protection scheme to prevent a child from accessing roads 201-202 unsupervised for safety of the child. However, if an MCD associated with the child has a large error boundary, the child's safety may be compromised. For example, in FIG. 3, a first child's MCD may have a location 210-1 and a second child's MCD may have a location 210-2. Locations 210-1 and 210-2 may respectively have error boundaries 211-1 and 211-2, which are defined by radii 212-1 and 212-2 respectively.
In this example, the first child represented by location 210-1, which is outside of geofence 301, and the second child represented by location 210-2, which is within geofence 301, would both be in danger since overlapping regions 302 formed by error boundary 211-1 and geofence 301, and overlapping region 303 formed by error boundary 211-2 and geofence 301 may indicate that both children are within geofence 301, thereby being within a safe region. However, in actuality the children can be outside of geofence 301. The responses in both of these cases therefore would be undesirable (i.e., a false positive alert). Furthermore, the sensitivity range and bounce range of a tracked MCD (e.g., MCD 101) would make establishment of an accurate geofence difficult as the error boundary is not always fixed. As described above, such would cause false alerts to be registered and real or true alerts to be ignored or unregistered, thereby causing critical geofence applications to be ineffective except for very loosely controlled applications.